The War of the Roses in the 15th Century, fought between the House of Lancaster (the red rose) and the House of York (the white rose) created a sense of bitterness between the two areas from either side of the Pennines that has never truly disappeared. The fact one team plays in red and the other in white (well, since 1961 anyway) only accentuates that link. It is also a fact that Manchester and Leeds were rivals for business during the Industrial Revolution during the 18th and 19th centuries, and even now compete for new companies investing in the cities.